Various surgical procedures are performed by medical specialists such as cardiologists and radiologists, utilizing percutaneous entry into a blood vessel. To facilitate cardiovascular procedures, a needle is introduced through the skin and into a target blood vessel, often the femoral artery. The needle forms a puncture through the blood vessel wall at the distal end of a tract that extends through the overlying tissue A guide wire is introduced through a bore of the needle before the needle is withdrawn over the guide wire. An introducer sheath is next advanced over the guide wire. The sheath and guide wire are left in place to provide access during subsequent procedures.
The sheath facilitates passage of a variety of diagnostic and therapeutic instruments and devices into the vessel and its tributaries. Such diagnostic procedures may include angiography, intravascular ultrasonic imaging, and the like. Typical interventional procedures include angioplasty, atherectomy, stent and graft placement, embolization, and the like. After a procedure is completed, the catheters, guide wire, and introducer sheath are removed, and it is necessary to close the vascular puncture to provide hemostasis and allow healing
The common technique for achieving hemostasis is to apply pressure, either manually or mechanically, on the patient's body in the region of the tissue tract and vascular puncture. Typically, pressure is applied manually and subsequently is maintained through the use of mechanical clamps and other pressure-applying devices. While effective in most cases, the application of external pressure to the patients skin presents a number of disadvantages. For example, when applied manually, the procedure is time-consuming and requires the presence of a medical professional for thirty minutes or more. For both manual and mechanical pressure application, the procedure is uncomfortable for the patient and frequently requires the administration of analgesics to be tolerable.
Moreover, complications from manual pressure application are common The application of excessive pressure can occlude the underlying artery, resulting in ischemia and/or thrombosis. Even after hemostasis has apparently been achieved, the patient must remain immobile and under observation for hours to prevent dislodgment of the clot and to assure that bleeding from the puncture wound does not resume. Renewed bleeding through the tissue tract is not uncommon which can result in hematoma, pseudoaneurisms, and arteriovenous fistulas. Such complications may require blood transfusion, surgical intervention, or other corrective procedures. The risk of these complications increases with the use of larger sheath sizes, which are frequently necessary in interventional procedures, and when the patient is anticoagulated with heparin or other drugs.
As a result, several alternatives to the manual pressure hemostasis technique have been proposed to address the problem of sealing the opening in vessel wall following percutaneous transcatheter procedures. For example, bioabsorbable, thrombogenic plugs comprising collagen and other materials have been used at the vessel wall opening to stop bleeding. These large hemostasis plugs stimulate blood coagulation at the vessel opening. Other techniques provide for the use of small dissolvable disks or anchors that are placed in the vessel to block or clamp the opening.
Additional techniques use needles and sutures to ligate the opening. The needle is and sutures are delivered through a catheter Obviously, any suturing procedure carried out through a catheter or tube requires a high level of skill.
Another technique involves the injection of a procoagulant into the opening with a balloon catheter blocking inside the vessel lumen. However, it is possible for the clotting agent to leak past the balloon into the vessel lumen and cause stenosis.
Lasers and radio-frequency (RF) energy have also been used to thermally fuse or weld the punctured tissue together. Other more recent techniques involve the use of high frequency ultrasound (HIFU) energy.
While all of the above procedures have advantages and disadvantages, no current procedure addresses the problem of informing the physician of the orientation of the opening on the vessel. Specifically, the operating physician typically does not know whether the needle that penetrates the vessel wall penetrated the vessel at the top, towards the right side of the vessel or towards the left side of the vessel (from the physician's perspective or from a top view). Knowledge of the orientation of the opening in the vessel would be beneficial for purposes of deciding which closure technique to employ Referring to figures and 1-5, it would be beneficial for the physician to know whether (a) the opening passes through a top area of the vessel 24 as shown by the opening 21 of FIGS. 1, 2 and 4, or whether (b) the opening passes through either a right side of the vessel 24 as shown by the opening 22 of FIGS. 1, 2 and 5, or (c) whether the opening passes through a left side of the vessel 24 as shown by the opening 23 of FIGS. 1, 2 and 3. The orientation of the opening 21, 22 or 23, from the physician's top view of the vessel or artery 24, would be a factor in determining the correct closure technique. Specifically, certain closure techniques may be approptiate for a top orientation (or “top stick”) but not appropriate for side orientations (or “side sticks”) In summary, deciding between sutures, a plug, RF or HIFU may depend upon orientation of the opening.
Accordingly, there is a need for devices and methods for determining the orientation of a vascular opening created during an intravascular procedure so that the appropriate closure technique may be utilized upon completion of the intravascular procedure.